Apparatus for lowering people from buildings and the like

ABSTRACT

An apparatus for lowering people from a building or platform which includes a lowering line that is looped through a block member having a cylindrical ratchet with a grooved rim that is rotatably mounted on a shaft centrally positioned between two side plates forming the sides of the block member. The block member includes a longitudinal axis extending through the center of the shaft mounting the cylindrical ratchet and includes an attaching device which is offset a predetermined distance to one side of the longitudinal axis. On the opposite side of the block member from the attaching device is a pair of spaced pivots which make up a narrow entry and exit opening through which the incoming and outgoing ends of the lowering line extend. The pivots are equally spaced on either side of the longitudinal axis with the outgoing end of the lowering line passing adjacent to the pivot which is arranged on the opposite side of the longitudinal axis from the attaching device. The grooved rim of the cylindrical ratchet is formed as a pair of side walls which taper inward at a predetermined angle so as to produce friction between the side walls of the ratchet rim and the lowering line when a load is placed on the outgoing end of the line. A load on the lowering line causes a pawl to engage the ratchet and lock it from rotating in the downward direction and causes the block member to tilt toward the side corresponding to the outgoing end of the lowering line to bend the line around the pivot to increase and control the friction on the lowering line.

The invention comprises an apparatus as stated for lowering people,particularly from buildings, platforms, posts and the like.

BACKGROUND OF THE INVENTION

Swedish Patent no. 452,951 describes a lowering apparatus that is to beused from buildings. This apparatus is not suited for universalapplications. It is poorly suited for suspending people from their bodywhich is required for mast assembly workers on oil platforms and thelike.

U.S. Pat. No. 659,093 describes a lowering apparatus with a rope blockwhere a grooved brake lever acts as the brake unit. However, the brakingeffect is difficult to control and so this device may not be too easy touse. The breaking effect is also difficult to adjust due to peoplehaving differing weights. This means that either children are loweredtoo slowly, or heavier adults will be lowered too quickly. Neither ofthese lowering devices are suited for releasing a person who is hangingunconscious, for example on a power line pole.

OBJECTIVE

The main objective of the invention is to design a lowering apparatusthat can be adjusted to various areas of application. A particularobjective is to design a lowering apparatus that is so light and compactthat it can be worn by mast assembly workers, for example, and thoseworking on high scaffolding and platforms. The lowering apparatus mustbe suitable to be used for releasing a worker in an emergency who ishanging from his pole climbing footwear on a power line pole.

SUMMARY OF THE INVENTION Principle

It has been found that the use of such a brake device in the statedconfiguration provides sufficient braking with a wide range of loads.This safely provides adequate braking in a variety of applications. Theapparatus makes it possible to stop the lowering process by a slightpull on the ingoing part of the line. A further advantage is that thenew apparatus can be made to be small and relatively light.

DESCRIPTION OF THE DRAWING

The invention will be described below with reference to the drawings,where

FIG. 1 illustrates a lowering situation where an apparatus in accordancewith the invention is used,

FIG. 2 shows a cross section of the block, and

FIG. 3 shows part of a section through the ratchet mechanism.

DETAILED DESCRIPTION OF THE DRAWING

FIG. 1 shows a power line post 11 with curved insulators 12. Here, thereis a person 13, who has become incapacitated or has touched a liveelement so that he/she cannot get down without help. The drawing showsthe lowering phase, after an assistant has secured the loweringapparatus in accordance with the invention, lifted the injured personfrom a hanging position, and loosened and removed that person's poleclimbing footwear.

The apparatus in accordance with the invention has three maincomponents: a securing line 14, a block 15 that the securing line 14 isattached to at one end, and a lowering line 16 which can be attached bya loop 17 around the upper part of a person 13 who requires help. Thesecuring line 14 can have its free end tied to a higher point, in thiscase a curved insulator 12. The block 15 is shown in more detail inFIGS. 2 and 3.

The block 15 has two parallel, rectangular side plates 18, one of theseis shown in FIG. 2. The side plates 18 support a ratchet 19 that isbetween them. This is freely mounted on a shaft 20 that in turn has itscentre attached to side plates. The ratchet 19 has a grooved rim 21 thathas parallel sides in the example. On the sides of the grooved rim 21there are teeth 22 for a bifurcated pawl 23. The bifurcated pawl 23,that will be described in more detail below, is mounted on a shaft pivot24 in a corner of the side plates 18. The pawl 23 is pressed to engagewith the teeth 22 by a spring 25 attached to the shaft pivot 24 andfixed to another pivot 26 located on the side of the shaft pivot 24, andalso attached to the side plates 18. The engagement end 27 of the pawl23 is bifurcated or forked so that it surrounds the lowering line 16without engaging it. The free end 28 of the pawl 23 protrudes outsidethe side plates 18 so that is accessible for release.

Near the rim of the ratchet 19 there is a pair of parallel pivots 29 and30, that have combined guiding and braking functions. The respectivedistance between pivots 29 and 30 and the distance of the pivots to theratchet 19 are adjusted to the diameter of the lowering line 16. Themode of operation will be described in more detail below.

At the upper edge of the side plates 18 in FIG. 2 there is a securingbolt 31 for the securing line 14 on the opposite side from the pawl 23.The securing bolt 31 for securing the support or attachment line 14 isoffset a dimension B from the longitudinal axis A of the block 15 whichpasses through the center of the shaft 20. This offset is on theopposite side of the block 15 from the pivot 30 and the loaded ordownward moving end M of the line 16. The securing line 14 has a hook 33on its free end that can be hooked over an anchor point above the user,either while he/she is in a work situation where there is a risk offalling, or as in the example, when there has been an accident and therescue crew is to lower the injured person.

The apparatus that is described in the example can also be used with asecuring line 14 placed around the upper part of the user's body, whilean end of the lowering line 16 is attached to a higher point. Thissolution may be satisfactory as a precaution, but is not suitable forrescue should an accident have occurred.

The apparatus in the example can be modified in various ways. The pawlcan, for example, be built into the ratchet so that it is accessible andcan be released through one of the side plates 18.

Also pivots 29 and 30 can be replaced by other types of guide units thattogether form a line guide opening 32. It is important that the lineguide opening 32 is statically independent without any external forcesbeing exerted, as is the case with the lowering apparatus in U.S. Pat.No. 659,093. If independent of such forces, the present invention willensure stable braking that cannot be influenced by external conditions,such as rain or other precipitation.

The groove 21 has side walls that result in wedging the lowering line.This provides braking between the ratchet 19 and the lowering line 16.The side walls of the groove 21 can be slightly convergent towards theirbase, with a maximum of about 20 degrees on each side. Preferably muchless, and under 7.5 degrees.

The offset dimension B for the securing bolt 31 and line 14 causes therectangular side plates 18 of the block 15 to tilt downward on the rightside as viewed in FIG. 2 when a load is applied to the downward movingend M of the line 16. This canting or tilting of the entire block 15causes the end M of the line 16 to crimp or bend around the pivot 30increasing the friction on the line 16 and holding the line in contactwith the perimeter of the ratchet groove 21. In this way a greaterfriction load can be produced on the line during the loading and use ofthe lowering apparatus according to the present invention.

I claim:
 1. An apparatus for lowering people from a high level, forexample from a building, a post, a platform or scaffolding, theapparatus including a lowering line that is looped through a blockmember having a cylindrical ratchet means with a grooved rim that isrotatably mounted on a shaft centrally positioned between two sideplates forming the sides of the block member, the improvement comprisinga pawl means that is pivotally mounted between said side plates and ispositioned to engage teeth formed around the outer perimeter of the rimof the ratchet means; said block member includes a longitudinal axisextending through the center of the shaft mounting said cylindricalratchet means; said block member includes attaching means which isoffset a predetermined distance to one side of said longitudinal axisand at the opposite end of said block member from said attaching meansis a narrow entry and exit opening means through which the incoming andoutgoing ends of the lowering line extend after passing around thecylindrical ratchet means; said narrow entry and exit opening meansbeing formed by a pair of spaced pivots equally spaced on either side ofsaid longitudinal axis with the outgoing end of the lowering linepassing adjacent to the pivot which is arranged on the opposite side ofthe longitudinal axis from the attaching means; said attaching meansincludes an anchor pin attached between said side plates and anattachment line connected to said anchor pin which extends outwardlyfrom said block member so that it can be attached to a secure object forsuspending the apparatus; and the grooved rim of the ratchet means isformed as a pair of side walls which taper inward at a predeterminedangle so as to produce friction between the side walls of the ratchetrim and the lowering line when a load is placed on the outgoing end ofthe lowering line causing the pawl means to engage the ratchet teeth andlock the ratchet means from rotating in the downward direction and causethe block member to tilt on a side corresponding to the pivot engagingthe outgoing end of the lowering line to bend the line around the pivotto increase the friction on the lowering line.
 2. An apparatus asdescribed in claim 1 wherein the pawl means has a bifurcated end whichis arranged to engage the teeth formed on the perimeter of the groovedrim of the cylindrical ratchet means, the bifurcated end being arrangedto straddle the lowering line positioned in the grooved rim of theratchet means.
 3. An apparatus as described in claim 1 wherein the pawlmeans is elongated and rotatably mounted so that the end of the pawlmeans opposite the end which engages the teeth on the rim of the ratchetmeans is exposed beyond the block member so that the pawl means can bemanually moved to disengage from the teeth on the rim of the ratchetmeans.
 4. An apparatus as described in claim 1 wherein each of the sidewalls of the grooved rim taper inwardly at an angle of 1-15 degrees. 5.An apparatus as described in claim 4 wherein the taper angle on each ofsaid side walls is less than 7.5 degrees.